Method and apparatus for antifoam filling a container



0, 1968 1 N. A. KELLY 3,415,294

METHOD AND APPARATUS FOR ANTIFOAM FILLING A CONTAINER Filed May 1. 1967I 2 Sheets-Sheet 1 NORMAN A. KELLY INVENTOR.

as wW M ATTORNEY Dec. 10, 1968 KELLY 3,415,294

METHOD AND APPARATUS FOR ANTIFOAM FILLING A CONTAINER Filed May 1, 19672 Sheets-Sheet 2 FIG. 6

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NORMAN A. KELLY INVENTOR.

BY M

AT TOR NEY United States Patent 3,415,294 METHOD AND APPARATUS FORANTEFOAM FILLING A CONTAINER Norman A. Kelly, Warsaw, llnd., assignor toHaslron, Inc., Warsaw, Ind., a corporation of DelawareContinuation-impart of application Ser. No. 418,987, Dec. 17, 1964. Thisapplication May 1, 1967, Ser. No. 635,096

11 Claims. (Cl. 1411) ABSTRACT OF THE DISCLOSURE This invention relatesto a filling machine for introducing liquids into a container Whileminimizing the formation of foam, and comprises a plurality ofrelatively closely spaced fine mesh screens at the discharge openingwhereby the effective head on the liquid is substantially reduced. Inthis manner, a higher head pressure can be used while the liquid atdischarge has a minimum of energy.

The present application is a continuation-in-part of my priorapplication Ser. No. 418,987, filed Dec. 17, 1964, which application hasbeen abandoned upon filing this application.

This invention relates in general to a machine for filling containersand, more particularly, to a dispensing device for such a machine and toa method for minimizing, if not eliminating, the formation of foam whichhas heretofore occurred When certain types of liquids have been pouredinto containers.

Container filling machines have been used for many years in a widevariety of industrial and commercial situations, as for example, to fillcontainers with beverages. However, certain beverages, such as milk,tend to foam during a container filling operation, particularly where arelatively fast filling rate is employed. Numerous attempts hvae beenmade to overcome this troublesome problem and some of these attempts aredisclosed in the S. D. Potter Patent No. 2,901,009, the E. P. KingPatent No. 2,775,486, the C. L. Day et al. Patent No. 2,724,535, and theC. W. Heinle Patent No. 2,380,434. To the best of applicants knowledge,none of the existing devices for minimizing the formation of foam havebeen both commercially acceptable and capable of completely satisfactoryoperation. In fact, it has become generally accepted by users and makersof container filling machines that it is not practicable to stopfoaming. Thus, various types of apparatus have been developed forsuccessfully removing the foam.

The most common procedure for removing foam involves the insertion of atube into each bottle as it is being filled so that the foam can bedrawn out of the bottle as it reaches the top thereof. In an averagedairy or other filling operation, the milk or other beverage containedin the foam or, in other words, from which the foam is formed, can berather substantial over a period of time. However, the laws governingthe sanitation and handling of beverages for human consumption usuallyprohibit the use for human consumption of the beverage removed in thefoam. Thus, the disposal of such foam produces a further problem andexpense.

Where, for example, the filling machine is operated at a fairly highrate of speed, the loss of beverage through the foaming action canadversely affect the filling accuracy of the filling machine,particularly where the filling is controlled by a time rate of flow.Thus, the bottle is often slightly over-filled in order to ensure fullmeasure, which creates a further loss or expense.

Specific reference is made herein to the use of the invention onmachines for filling containers with milk, because it was out of thisbackground that the specific disclosure developed. However, theinvention is clearly adapted for a variety of uses or for use in pouringliquids other than milk where reduction or elimination of foam isdesired.

A brief discussion of the prior art relating to the specific details ofthe applicants dispensing device is believed to be in order. Onecritical feature in applicants dispensing device resides in a plurality,e.g., a pair, of relatively closely spaced screens located in thepassageway from the control valve in the dispensing device, as shown inFIGURE 4 of the drawings. Heretofore, this arrangement of screens hasbeen deemed wholly unsuited for the purpose of reducing foam, asevidenced by a number of prior art patents which have depended upon thisvery same arrangement for increasing the production of foam. Forexample, the Wager Patent No. 1,554,147 uses a plurality of spacedscreens specifically for the purpose of forming lather. The J. A. RicePatent No. 2,089,813 discloses the use of spaced screens for the purposeof introducing bubbles into the cement slurry The Holm-berg et al.Patent No. 2,100,165 shows a pair of spaced perforate members for theexpress purpose of producing a large spray covering an areaapproximately four times the area covered by a solid column issuingdirect from a half-inch spout or through the ordinary strainer nozzle,and the jets issuing through the spray holes will have much greaterforce, and the back pressure is correspondingly increased The B.Sheldon, Jr., Patent No. 2,492,327 shows the use of a pair of spacedscreens for the express purpose of producing a larger and finer head onbeer as it is poured into a container. In fact, the Sheldon device isintended to produce a longer lasting head or foam, which wouldcompletely defeat applicants purposes. From the foregoing comments, itcan be seen that, for the most part, the prior art disclosures, whichresemble applicants device, have taught the very reverse of that whichapplicant has accomplished.

Accordingly, the objects and purposes of this invention have been theprovision of:

l) A filling machine for filling containers with a liquid that normallytends to foam when poured, which machine includes an antifoaming headwhereby the formation of foam is minimized, if not eliminated;

(2) A filling device, as aforesaid, which is adapted for use on existingfilling machines with little or no change in the machine other thanreplacing the filling devices, which is adapted for use with a varietyof different types of liquids having varying viscosities, which does notmaterially alter the operation of the machine except for the reductionof foam, which is easily and quickly disassembled and reassembled suchas for cleaning purposes, and which has a minimum of parts;

(3) An antifoaming head, as aforesaid, which is foolproof in operation,small in size, inexpensive to manufacture and adapts itself readily tothe normal functioning of the valve mechanism to which it is attached;

(4) A method of minimizing, if not eliminating, the formation of foamwhen certain liquids, such as milk, are poured by a filling machine intocontainers.

The objects and purposes of the invention, including those set forthabove, have been met by providing an apparatus and a method for fillinga container with a liquid that normally tends to foam, while minimizingsuch foaming. Specifically, the method and apparatus of this inventioncomprises passing the liquid through a dispensing device equipped with adischarge valve and an antifoaming head that includes a plurality ofclosely spaced screens. The dispensing device is embodied in a fillingmachine wherein it is connected to a supply of liquid, such as milk, andis designed and arranged so that the liquid is dispensed into acontainer placed below and adjacent the dispensing device. In thepreferred embodiment, a plurality of dispensing devices are used in aline so that the filled containers can be delivered individually atshort intervals to a capping apparatus.

Other objects and purposes of this invention will become apparent topersons familiar with this type of equipment upon reading the followingdescriptive material and examining the accompanying drawings, in which:

FIGURE 1 is a fragmentary, front elevational view of a container fillingmachine having a plurality of filling devices including the antifoaminghead of the invention.

FIGURE 2 is a sectional view substantially as taken along the line IIIIin FIGURE 1.

FIGURE 3 is an enlarged sectional view taken along the line III-III inFIGURE 1.

FIGURE 4 is a sectional view taken along the line IV-IV in FIGURE 3.

FIGURE 5 is an exploded enlarged sectional view substantially as takenalong the line VV in FIGURE 4.

FIGURE 6 is an enlarged sectional view taken along the line VI-VI inFIGURE 3.

FIGURE 7 is a fragmentary detail sectional view of a modified form ofthe present invention.

For convenience in description, the terms upper, lower and words ofsimilar import will have reference to the filling device of theinvention as appearing in FIG- URES 1, 2 and 3. The terms inner, outerand derivatives thereof will have reference to the geometric center ofsaid filling machine, said filling device and parts thereof.

The filling machine 10 (FIGURES 1 and 2) is of the time-fill type and isequipped with four dispensing or filling devices 11, each of which isequipped with a valve 12 and an antifoaming head 13. A plurality ofcontainers 16 can be supported upon the conveyor 17 for intermittentmovement into and out of filling positions or stations S beneath saiddischarge devices 11. The dispensing devices 11 (FIGURE 2) are securedto and located beneath the bottom wall of a reservoir or tank 18 withwhich they are in communication for the purpose of dispensing theliquid, such as milk, from said tank into said containers 16.

The tank 18 may be connected to a bulk supply of the liquid, not shown,in a conventional manner by means of the conduit 19. Conventional flowcontrol mechanism 14 (FIGURE 1) may be provided for controlling the flowof liquid from said supply through said conduit so that the level ofliquid in said tank 18 is maintained at a substantially constant level,whereby accurate filling can be achieved. That is, since a time-filltype filling machine is dependent upon a constant rate of flow, it isessential that the head pressure, hence the liquid level, within thetank 18 be maintained substantially constant. When timefill typemachines are used for handling milk, the depth of the milk in the tankor reservoir is usually about 12 inches. However, the dispensing devicecan be adapted for use on filling machines wherein the depth of theliquid is substantially smaller or greater than 12 inches. Theillustrated machine 10 also has a control panel 22 and a containercapping apparatus 23.

The conveyor 17 (FIGURE 1) includes a central platform 24 and endlessbelt 26 which moves the containers onto the central platform 24 at theright end thereof. An endless belt 27 receives the containers from thecentral platform at the left end thereof. A pair of guide bars and(FIGURES l and 2) extend along the sides of and above the conveyor 17for the purpose of preventing frontward or rearward movement of the containers 16 out of their desired path beneath the dispensing devices 1.1.

The conveyor 17 also includes a plurality of fingers 28 which are partof a transfer mechanism 21 which reciprocates the fingers 28 lengthwiseand crosswise of said platform 24, whereby the containers are engagedand accurately moved into and out of the filling stations S S S and Srespectively, beneath the four dispensing devices 11, which are locatedin a line substantially directly above and parallel with the path ofmovement of the con tainers. The fingers 28 (FIGURE 1) extend rearwardlyand then downwardly where they are connected to a bar 29 which ispivotally supported upon the filling machine 10 for pivotal movementaround its lengthwise axis. The bar 29 is also supported for movementlengthwise of the machine by means such as the power cylinder 30, whichis connected between the machine frame and the bar 29. Pivotal movementof the bar 29 (FIGURE 2) may be effected by any convenient means such asa power cylinder 35, which is connected between a pair of the fingers 28and the machine frame.

As shown in FIGURE 2, a microswitch 40 having a sensing element 39 ismounted upon the rear side of the filling machine frame adjacent theplatform 24 and near the leftward edge (FIGURE 1) of each fillingstation S. Thus, the sensing element 39 is engaged by the container 16just as it is moved into its filling position in each filling station.

Each of the dispensers 11 (FIGURES 3 and 4) which are preferablyidentical is comprised of a mounting member 31, a valve housing 32 andthe control valve .12 which includes a valve stem 33 with a valve head34 on the lower end thereof.

The mounting member '31 (FIGURE 4) is comprised of an elongated cylinder36 having an annular, outwardly extending flange 37 connected to theupper end thereof. The flange may be beveled on its lower side forreception into a beveled opening 38 in the lower wall 15 of the tank 18.The cylinder 36 is externally threaded at 42 adjacent the flange 37 forthreaded engagement by a nut 43, whereby the adjacent portion of thelower wall 15 and a washer 44 are clamped against the flange 37 in aliquid-tight connection.

The valve housing 32 has an upper, cylindrical portion 46 which isslideable and telescopically received upon the lower end of the cylinder36 of the mounting member 31. The cylinder 36 has an annular groove 47near its lower end into which an O-ring 48 is received to provide aliquid-tight sliding seal between the mounting member 31 and the valvehousing 32. The upper cylindrical portion 46 has an annular outwardlyextending flange 51 diametrically aligned, outwardly opening recesses 52and 53 into which a pair of pins 54 and 55 are snugly received.

The valve housing 32 has a lower cylindrical portion 57 which ispreferably coaxial with and of less diameter than the upper cylindricalportion 46. An outwardly extending, annular flange 58 is secured uponthe valve housing 32 at the junction of the lower cylindrical portion 57with the upper cylindrical portion 46.

The mounting member 31 (FIGURE 4) has an upwardly extending anddownwardly opening, U-shaped support bracket 61 which is secured to theupper side of the flange 37 so that it straddles the bore 64 in themounting member 31. The web 62 of the bracket 61 has a central opening63 which is preferably coaxial with the bore 64 of the mounting member31.

The valve stem 33 (FIGURE 4), which is substantially smaller in diameterthan and is coaxially disposed within the bore 64 of the mounting member31, has an annular, outwardly extending flange 66 near its upper end. Apreferably resilient washer 67 is sleeved upon the valve stem 33directly above the flange 66 for engagement with the lower side of theweb 62 when the upper end of the stem 33 extends upwardly through theopening 63 in said web 62, as shown in FIGURE 3. The stem 33 has anannular groove 68, above the flange 66, into which the resilientlyflexible elements 69 of a spring clip 70 are removably received for thepurpose of supporting the stem 33 upon the bracket 61.

The valve head 34 (FIGURE 4) is integral with the lower end of the valvestem 33 and is spaced downwardly from the lower end of the mountingmember 31 when the flange 66 is against the web 62. The lower face 73 ofsaid valve head is conically shaped in a downwardly converging directionfor liquid-tight engagement with a downwardly converging, conical andannular valve seat 74, located at the junction between the cylindricalupper portion 46 and cylindrical lower portion 57 of the valve housing32.

The valve housing 32 (FIGURE 2) is vertically reciprocated by anoperating mechanism 76 including a yoke 77 which is connected to an arm78 so that the yoke extends around the housing 32 in the vicinity of theflange 51. The free ends of the yoke 77 are bifurcated to provide a pairof upper elements 79 and 80 (FIGURE 4) and a pair of lower elements 82and 83 spaced from the upper elements. The pins 54 and 55 extend snuglybetween the upper elements 79 and 80 and the corresponding lowerelements 82 and 83 for effecting positive, upward and downward movementof the housing 32 with respect to the mounting member 31. The arm 78 maybe connected to an actuating element 84 which, for example, may be asolenoid, for effecting the vertical movement of the arm 78, hence ofthe valve housing 32.

The antifoaming head 13 (FIGURE 5) is comprised of a cylindrical shell85 having an inwardly extending, annular flange 86 connected to thelower end thereof. The inside diameter of the bore 87 in the shell 85 ispreferably only slightly greater than the outside diameter of the lowercylindrical portion 57 of the valve housing 32. The shell 85 has a pairof diametrically disposed circumferentially elongated openings 88 and 89(FIGURE 6) which are alignable with an annular groove 92 in thecylindrical lower portion 57 when the shell is sleeved on the lowerportion 57 and the upper edge of the cylindrical shell 85 is spaceddownwardly a short distance from the lower flange 58.

The shell 85 is supported upon the cylindrical lower portion 57 by meansof a bifurcated plate 93 having a pair of spaced, substantially coplanarstrips 94 and 95, the opposing edges of which are simultaneously andslideably receivable into the openings 88 and 89 and the adjacentportions of the groove 92, as shown in FIGURE 6. The plate 93 has aflange 97 at one end thereof for manually gripping the plate 93 toeffect its attachment to and removal from the shell 85 and valve housing32.

A pair of resiliently flexible, annular seals, such as the O-rings 98and 99 (FIGURES 4 and 5) are snugly, but removably, disposed within thebore 87 between the flange 86 and the lower axial face 102 of thecylindrical portion 57. Av pair of circular, perforate members, such asthe screens 103 and 104, are removably disposed within the shell 85. Theupper screen 103 is located between the O-rings 98 and 99, and the lowerscreen 104 is located between the lower O-ring 99 and the flange 86, inthis particular embodiment. When the shell 85 is held in position uponthe cylindrical portion 57 by means of the plate 93, with the O-rings 98and 99 and the screens 103 and 104 in their above-described places inthe bore 87, said O-rings 98 and 99 are held under slight compression.This compression causes the O-ring 98 to serve also as a seal betweenthe cylindrical portion 57 of the housing 32 and the adjacent portion ofthe shell 85 to prevent the escape of liquid therebetween.

In applications wherein the liquid flowing through the dispensingdevices is milk, the mesh of the screens 103 and 104 is preferablyselected so that the open area through each screen is preferably lessthan about 50% of the crosssectional area of the bore or passageway 106in the lower portion 57. The cross-sectional area of the passageway 106is preferably substantially less than the minimum cross-sectional areathrough the throat 107 between the valve head 34 and the valve seat 74,when the control valve 12- is in its open position of FIGURE 5. Thus,there is not possibility of starving the flow of liquid through thepassageway 106 during the normaloperation of the dispensing device 11. v

The diameter of the passageway 106 is advantageously approximatelythree-quarters of an inch where the liquid stands approximately 12inches deep in the tank 18. If the depth is increased, the mesh of thescreens could be reduced and/or additional, spaced screens could beadded to compensate for the increased head pressure, and thereby avoidan increase in foam.

Using dispensing devices 11 substantially identical with those describedabove, it was found under actual commercial use that a gallon containercould be filled with milk, either by one continuous filling operation orin a series of partial filling operations, by means of said dispensingdevices without creating more than a negligible amount of foam withinthe gallon container. Moreover, said containers could be filled by saiddispensing devices at a speed comparable to that achieved by fillingmachines of the foam forming types, which are presently in general use.A negligible amount of foam, as stated above is intended to include afoam accumulation on the top of the milk in a filled gallon containerwhich would be substantially less than a half inch above the top of theliquid immediately following a filling operation. In some instances,depending upon the filling procedure, the amount of foam occurring ontop of the milk in a full gallon container immediately following thefilling operation would be less than a quarter of an inch thick and, inmost instances this foam dissipates quickly. In any event, the amount offoam which is formed does not spill out of the container and it does notaffect in the slightest the accurate filling of the container.

In operation of the machine illustrated in FIGURE 1, a plurality ofcontainers 16- (FIGURE 1) are placed upon the endless belt 26, the upperreach of which may be urged in a conventional manner toward the platform24. The containers 16 are moved, one at a time, from the belt 26 ontothe platform 24 by the transfer mechanism 21. In accomplishing thismovement, each finger 28 is simultaneously moved rearwardly away fromthe platform 24 by the cylinder 35, then rightwardly by the cylinder 30,then frontwardly over the platform and the adjacent portion of the belt26 by the cylinder and fina lly leftwardly back into the initialposition by the cylinder 30.

As each container 16 enters station S the sensing element 39 on themicroswitch at station S is engaged, energizing the actuating element 84so that the arm 78 is moved downwardly whereby the yoke 77 will open thecontrol valve 12 by lowering the valve housing 32 associated with thedispensing device 11 at station S After a pre-selected time interval asdetermined by the setting of the controls 22, the operating mechanism 76is automatically operated to close the valve and thereby terminate thefilling operation. In the illustrated machine, the container at thistime is one-fourth full. The transfer mechanism 21, including thefingers 28, is operated again, whereby the first container is moved intothe second station S and, simultaneously, a second container is movedinto the first station 8;. The sequence of opening the valve 12 in thedispensing devices above stations S and S and filling the containers isnow performed in stations S and S because their associated microswitches40 are operated by the two containers.

This performance is repeated for each container until it is completelyand finally filled by the dispensing device in station S after whicheach filled container is moved by the mechanism 21 into the cappingposition beneath the capping apparatus 23. The transfer mechanism 21then moves the filled and capped container onto the endless belt 27,which carries the container away to a position for loading, as into acrate.

It will be recognized that a result substantially similar to thatachieved by the above-described structure can also be achieved whereinthe valve housing 32 remains stationary and the valve head 34, hence thevalve stem 33 is vertically reciprocated. This would be accomplished byconnecting the stem 33 to means for effecting its verticalreciprocation. In such case, it would be advantageous to integrate thevalve housing 32 with the mounting member 31.

The method of the invention can be carried out by using the equipmentdescribed above.

It would appear that the method and apparatus in accordance with thisinvention functions to reduce foaming by reducing the head pressure onthe liquid at the discharge opening, that is, at the opening 90, and bybreaking up the stream discharging from the opening into a plurality ofsmall streams to reduce the vortex action. Each of these points arehereinafter discussed.

The delivery rate of the liquid from the opening 90 is a function of thehead pressure, the flow resistance in the flow path, and the area of theopening. If the head pressure or the area of the opening 90 wereincreased or decreased, or if the flow resistance were decreased orincreased, the delivery rate of the liquid from the opening would becorrespondingly increased or decreased. In the selection of anycombination of values for these factors, the relevant considerationswould be that:

(a) The container must be filled in a minimum of time and require aminimum investment in filling machinery, space and operating expenses.

(b) The delivery rate of the liquid can be increased by increasing thevelocity of the liquid through the opening 90, which can be accomplishedby increasing the head pressure. However, the greater the velocity ofthe liquid at the opening, the greater will be its energy at impact uponthe bottom of the container or the previously dispensed liquid in thebottom of the container and, thus, the greater will be foam formation.

(c) The delivery rate of the liquid can be increased by increasing thearea of the opening 90, but this is limited since the container to befilled is usually provided with a mouth of a certain size that is fixedby custom and usage, convenience, or filling and capping requirementsforexample, with milk containers, the public is use to milk bottles havingcertain size mouths and the filling and capping equipment at the dairiesis designed to operate with containers having such mouth dimensions, andthe opening 90 must discharge a stream of liquid in a commercialoperation that will pass through the bottle mouth without spilling.

((1) With respect to time-fill type operations wherein the fillingaccuracy is a function of maintaining a constant head pressure, andexcept when prohibitively expensive equipment is used, it is notuncommon to experience fluctuations of plus or minus one-quarter inch inthe level of the liquid from the desired constant level, and to minimizethe influence of such variations on the delivery rate, a substantialbase level of fluid must be maintained, that is, for example, a one-halfinch variation is percentagewise a smaller variation from a twelve inchlevel than it would be from a six inch level.

In accordance with this invention, it is proposed to reduce foaming in afilling operation substantially to the point of elimination byinterposing a relaitvely fine mesh perforate member and preferably ascreen in the flow path of the liquid whereby the resistance to the flowis increased and, with the resultant pressure drop across the screen,the pressure on the liquid at the discharge opening 90 is decreased. Byincreasing the number of screens employed, the resistance can beincreased until the pressure on the liquid at the discharge opening issufficiently low to avoid foaming. Minimum foaming would be presentwhere the liquid pressure at the opening is substantially zero and theliquid has a dead fall from the opening into the container. It willhowever be apparent that in some circumstances less than a dead fall ofthe liquid would be satisfactory in that the amount of foam formed wouldbe acceptable and would not be troublesome. At the same time, maximumliquid pressure at the discharge opening consistent with a tolerablefoam level would be desirable since it increases the delivery rate.

Thus, the liquid pressure at the opening is limited by the foamcharacteristics of the liquid and is established by the liquid pressureat the inlet to the screens and by the open area, mesh and the numberand spacing of the screens. In a time-fill type installation, thepressure of the liquid at the inlet to the screens is in turnestablished by the head required in the tank to reduce to acceptablelevels the effects of variations in the head that are inherent incommercial quality equipment.

As an example of a typical installation, it has been found that, withmilk, substantially foam-free filling of a container can be obtained bythe use of a pair of 30 X 30 mesh screens in a discharge opening 90 thatis about 0.690" in diameter and with substantially 12" of head (a littlemore than 0.40 p.s.i.). The screens were formed of stainless steel wireabout 0.012 in diameter so that the effective area of the dischargeopening 90 was approximately 40% of the total area. The flow ratethrough this opening was sufficient to deliver one quart of milk inabout 3.1 seconds.

While it is not intended to limit the invention to the theory involved,it would appear that the presence of the screens such as the screens 103and 104 also tends to minimize the vortex action. As a single relativelylarge stream of liquid emerges from the discharge opening, it tends toassume a rotation which represents a certain amount of energy. Thus,when this stream falls into the liquid previously delivered into thecontainer, this energy is absorbed by the liquid which thus tends torotate with the incoming stream. The energy is eventually dissipated infriction in the liquid and between the liquid and the container, but inthe meantime, the rotation of the liquid has developed a vortex whichtends to permit more air to be trapped between the incoming stream andthe converging wall of the vortex. This trapped air constitutes foam. Atthe same time, the rotation of the stream itself tends to trap air infold-like formations in the liquid at the periphery of the stream, whichair also constitutes foam. The rotating stream is also more stable andthus penetrates deeper into the liquid in the container. With the liquidpassing through the large number of openings afforded by the screenopenings, it would appear that there is eliminated whatever tendencythere is for the individual streams to rotate. At the same time, withrelatively low head pressure and small openings that are closely spaced,the surface tension of the liquid prevents the stream from breaking upinto a plurality of small streams. As a result, the liquid emerges fromthe discharge opening as a single stream that is free of any discerniblerotation about its axis.

A further advantage of the screens is that, through the surface tensionof the liquid, they act to seal the discharge opening when the valvehead 34 is engaged with the valve seat 74 and the valve is thus closed,the flow is stopped immediately. Normally it would be expected that theliquid beyond the closed valve would continue to drain into thecontainer at a decreasing rate so that, either the container must beleft beneath the discharge opening for an appreciable period of time toreceive the drippings, or else these drippings will be spilled, whichnot only constitutes waste but also presents a sanitation and cleaningproblem. With the apparatus in accordance with this invention, thesurface tension of the liquid in the absence of any appreciable head,causes the liquid to adhere to the screens thereby forming a seal. Thus,the liquid that is past the valve when the valve is closed but is notpast the last screen 104, is held in the discharge opening 90 byatmospheric pressure and the surface tension of the liquid, and the flowis thus stopped immediately upon closing the valve.

Another feature of the present invention is that the flow path is sodesigned that there is no tendency for air '9 to be drawn into thedischarge opening 90. Normally, if the liquid were permitted to passfrom one diameter to a larger diameter, or if the velocity werepermitted to increase, for example as in a free fall, so that thediameter of the stream tended to-neck down and thus become smaller thanthe diameter of the conduit in which it is confined, the tendency wouldbe to create a vacuum that could draw air into the system. In theapparatus in accordance with this invention, the flow resistance imposedby the screens 103 and 104 tends to keep the liquid above the same underpressure so there is no tendency to create a vacuum. Between the screens103 and 104, the flow resistance imposed by the lower screen keeps theliquid under pressure.

While the perforate members 103 and 104 are preferably screens, sincescreens are relatively inexpensive and can be used as throw-away items,it will be apparent that equivalent screen-like elements such as a dischaving a plurality of relatively fine holes drilled or punched thereincould also be used. As herein used, the term perforate member refers toa screen or equivalent screen-like member having a plurality ofrelatively fine holes therein.

In FIGURE 7 there is illustrated a modification of the invention (wherein the inwardly extending annular flange 86a of the shell 85a has aninclined face 108 that converges downwardly. For supporting the screens103a and 104a there is formed .a small ledge 109 between the insidediameter 87a of the shell 85a and the inclined face 108 upon which thelower screen 104a is seated, with the O-rings 98a and 99a and the upperscreen 103a being stacked thereon as in the construction of FIGURE 4 andcompressed by the lower face 102a of the lower portion 57a of the valvehousing. Thus, when the stream of liquid emerges from the lower screen104a, it engages a converging surface which prevents the stream fromseparating from the wall as it accelerates in its free fall and thustends to neck down. In this manner, air cannot be drawn into any voidbetween the wall 108 and the stream .and thus be trapped in the stream.

Although particular preferred embodiments .of the invention have beendescribed above for illustrative purposes, it will be understood thatvariations or modifications of such disclosure, which come within thescope of the appended claims, are fully contemplated.

What I claim and desire to protect by Letters Patent is:

1. Apparatus for dispensing into a container a liquid which tends tofoam when it is poured while minimizing the amount of foam formed duringthe dispensing operation, comprising,

a frame structure having support means upon which 'the container can beplaced in a filling station,

a dispensing device having a passageway and arranged to discharge liquidfrom said passageway into a container located in said filling station,

means for supplying liquid under pressure to said passageway,

valve means in said passageway,

means for opening and closing said valve means,

an antifoamin g head having a bore open only at its opposite ends, meansfor mounting said antifoaming head on said dispensing device with saidbore communicating at one end with said passageway downstream from saidvalve means and at its other end with atmosphere,

and a plurality of spaced, perforate members held within and extendingacross said bore, the open area in each perforate member not materiallygreater than one-half the minimum cross-sectional area of saidpassageway between said perforate members and said valve.

2. Apparatus in accordance with claim 1 in which the open area in eachperforate member is substantially forty percent of the minimumcross-sectional area of said passageway between said perforate membersand said valve.

3. Apparatus in accordance with claim 1 in which said 10 plurality ofperforate members comprises a pair of closely spaced screens.

4. Apparatus in accordance with claim 1 in which said means forsupplying liquid under pressure to said passageway comprises a liquidreservoir means on said frame structure above said filling station,means for connecting said liquid reservoir means and said passageway,and means for maintaining a substantially constant pressure on saidliquid in said passageway adjacent said valve means.

5. Apparatus in accordance with claim 4 in which said means formaintaining a substantially constant pressure on said liquid comprisesmeans for maintaining a substantially constant level of liquid in saidliquid reservoir means.

6. Apparatus in accordance with claim 5 for dispensing milk or a similarliquid into containers in which said plurality of perforate memberscomprises a pair of closely spaced screens, .and wherein the diameter ofsaid passageway is substantially 0.690 inch, the open area of saidperforate members is substantially forty percent, and the level ofliquid in said liquid reservoir means is substantially twelve inches.

7. Apparatus in accordance with claim 1 in which said valve meanscomprises an annular valve seat in a valve housing and a valve stemhaving a valve head for cooperating with said valve seat to close theinlet to said passageway, means for supporting said valve housing andsaid valve stem so that said valve head and said valve seat are movablewith respect to each other and said passageway communicates with saidreservoir.

8. Apparatus in accordance with claim 7 in which said valve stem is heldin a fixed position relative to said liquid reservoir means and saidvalve housing cylindrical I and telescopically mounted upon acylindrical mounting member depending fromsaid reservoir, said valvehousing being movable endwise on said mounting member for movement ofsaid valve seat into and out of engagement with said valve head.

9. Apparatus in accordance with claim 7 in which said antifoaming headis a shell telescopically received upon said valve housing and having aninwardly projecting annular flange remote from said valve housing, saidperfiorate members being screens disposed within the bore of said shellbetween said flange and the end of said valve housing, and resilientpacking elements disposed one between said screens and one between theend of said valve housing and the adjacent screen, and means forreleasably securing said shell on said body member with said resilientpacking elements under compression.

10. Apparatus in accordance with claim 1 in which said antifoaming headhas a downwardly converging surface below said perforate members, saidconverging surface being disposed coaxially of said passageway andpresenting a relatively sharp edge .at the discharge end thereof.

11. In a process for dispensing milk into a plurality of containerswhile minimizing the amount of foam formed during the dispensingoperation, the steps comprising:

placing a supply of milk in a reservoir;

controlling the level of said milk in said reservoir to maintain .asubstantially constant level;

moving said containers sequentially into and out of a filling stationbeneath said reservoir;

intermittently opening and closing a valve means to permit said milk toflow by gravity into .a passageway communicating with said reservoir andlocated above said filling station;

passing said milk through a first plurality of relatively small openingsin said passageway below said valve means during a preselected intervalof time, said small openings being substantially within the samediametrical plane and having a total crosssectional area not materiallygreater than one-half of 1 1 1 2 the minimum cross-sectional area ofsaid passageway References Cited between said valve rneans and saidfirst openings; UNITED STATES PATENTS passing said m11k during saidpreselected time interval I through a second plurality of relativelysm'all open- 2124308 7/ 1938 MeZZ aPe5a 251-118 2,697,446 12/ 1954Harrington 25 11 18 ings below and spaced from said first openings, said5 second openings having approximately the same total cross-sectionalarea as said first openings, the milk HOUSTON BELL, JR., PrimaryExamzner, departing said second openings without substantial Us Cl XRhead pressure and in a substantially dead fall therefrom. 10 141156,286; 239-5533, 553.5, 590

